Photovoltaic devices are known in the art (e.g., see U.S. Pat. Nos. 6,784,361, 6,288,325, 6,613,603, and 6,123,824, the disclosures of which are hereby incorporated herein by reference). Photovoltaic devices can be generally classified as being either substrate-type devices, or superstrate-type devices. Substrate-type devices generally involve thin-film device coating layers being disposed on a rigid or flexible carrier (e.g., a glass substrate) such that the thin-film device coating layers are positioned between the carrier and the sun. On the other hand, superstrate-type devices generally involve a superstrate carrier (e.g., a glass superstrate) that is positioned between the sun and thin-film device coating layers.
Aside from a substrate or superstrate, photovoltaic devices typically include a front transparent electrode, a single- or multi-layer absorber that converts solar light into electricity, and a rear electrode that is usually opaque. For substrate-type devices, an opaque back electrode oftentimes is directly disposed on the back glass (or another intervening substrate). For superstrate-type devices, the transparent front electrode oftentimes is directly disposed on the superstrate. It is noted that the term “substrate” as used below is used in a generic sense and can refer to device front substrates, device superstrates, or other supporting (e.g., glass) substrates, unless otherwise noted.
Those skilled in the art know that device efficiency helps drive acceptance and/or viability of solar solutions in the marketplace of energy (or alternative energy) solutions. Thus, there is a constant struggle to improve the efficiency of photovoltaic devices.
Unfortunately, however, photovoltaic devices do not always produce energy at their predicted efficiencies, or even at efficiencies approximating predicted levels. While some advances have been made to improve efficiencies (e.g., by providing single- or dual-axis tracking systems), further improvements are still sought after by those skilled in the art.
Thus, it will be appreciated that there is a need in the art for improved photovoltaic devices and/or methods of making the same.
As explained in greater detail below, the inventors of the instant application have noted that the moisture that accumulates on photovoltaic modules can result in the leakage of the electrical current between the electrodes through the outside of the glass.
One aspect of certain example embodiments addresses this problem by introducing a high contact angle coating to one or more outer surfaces of the photovoltaic modules. By reducing the build up of moisture, leakages can be correspondingly reduced and efficiency can be correspondingly improved and/or made more consistent.
In certain example embodiments of this invention, a photovoltaic module is provided. Front and back substantially parallel, spaced apart glass substrates are provided. A semiconductor layer is sandwiched between first and second electrode layers. The semiconductor layer and the first and second electrode layers are all located between the front and back substrates. At least one hydrophobic coating is provided on an outermost surface of the back and/or front glass substrate(s), the at least one hydrophobic coating having an initial contact angle of at least 30 degrees.
In certain example embodiments of this invention, a method of making a photovoltaic module is provided. A first substrate with a hydrophobic coating disposed thereon is provided. A second substrate is provided. Either the first substrate or the second substrate supports a plurality of photovoltaic device layers, with the photovoltaic device layers comprising a semiconductor layer sandwiched between first and second electrode layers. The first and second substrates are connected together in substantially parallel spaced apart orientation to one another such that the hydrophobic coating is on an exterior surface of the first substrate, and such that the photovoltaic device layers are located between the first and second substrates. The hydrophobic coating has an initial contact angle of at least 30 degrees.
In certain example embodiments of this invention, a coated article including a glass substrate is provided. The substrate may support a hydrophobic coating having an initial contact angle of at least 50 degrees, more preferably at least 70 degrees on a first major surface thereof. A second major surface of the substrate, opposite the first major surface, may be adapted to support or be in direct or indirect contact with a plurality of thin film layers to be used as at least a part of a solar cell.
The features, aspects, advantages, and example embodiments described herein may be combined to realize yet further embodiments.